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Solar cells convert the sun's energy into electricity, similar to the way plants convert the sun's energy into food through photosynthesis. Solar cells work by using the sun's energy to enable electrons in semiconducting materials to move from orbits close to the nuclei of their atoms to higher orbits where they can conduct electricity. Commercial solar cells use silicon as the semiconductor, but here is a way to make a solar cell with more accessible materials to see for yourself how it works.

Steps

Part 1

Coating the Glass Plates

1

Obtain 2 equal-sized glass plates. Plates of the size used as covers for microscope slides would be ideal.

2

Clean both surfaces of the plates with alcohol. Once the plates are cleaned, handle them only by the edges.

3

Test the plate faces for conductivity. Do this by touching the surfaces with the leads from a multimeter. Once you have established which side of each plate is the conductive side, place them side by side, one plate conductive side up and the other conductive side down.

4

Apply transparent tape to the plates. This will hold the plates in place for the next step.

Place the tape along either of the long side of the plates to overlap 1 millimeter (1/25 inch) of the edges.

Place tape over the outer 4 to 5 millimeters (1/5 inch) of the conductive side up plate.

5

Apply a solution of titanium dioxide to the plates. Put 2 drops on the conductive side up plate, then spread it evenly over the plate surface. Allow the titanium dioxide to cover the conductive-side-down plate.

Before applying the titanium dioxide solution, you may first want to coat the plates with tin oxide.

6

Remove the tape and separate the plates. Now you'll treat the 2 plates differently.

Place the conductive-side-up plate on an electric hot plate overnight to bake the titanium dioxide onto the plate.

Clean the titanium dioxide off the conductive-side-down plate and place it where it won't collect dirt.

7

Prepare a shallow dish filled with dye. The dye can be made from raspberry, blackberry or pomegranate juice or by brewing a tea from red hibiscus petals.

8

Soak the titanium-dioxide-coated plate, coated side down, in the dye for 10 minutes.

9

Clean the other plate with alcohol. Do this while the titanium dioxide-coated plate is soaking.

10

Retest the cleaned plate to find its conductive side. Mark the side that doesn't conduct with a plus sign (+).

11

Apply a thin carbon coating to the conductive side of the cleaned plate. You can do this by going over the conductive side with a pencil or by applying a graphite lubricant. Cover the entire surface.

12

Take the titanium-dioxide-coated plate out of the dye. Rinse it twice, first with de-ionized water and then with alcohol. Blot dry after rinsing with a clean tissue.

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Part 1 Quiz

Why is it important to cover the plates with transparent tape?

The tape is part of the solar cell.

Nope! You'll eventually remove the tape. Make sure that the tape overlaps the edges of the plates when you put it on-- this is an important part! Click on another answer to find the right one...

To keep the plates in place.

Exactly! The tape keeps the plates in place while you apply the titanium dioxide. You will have one plate with the conductive side up and one plate with the conductive side down. Eventually, you'll have to treat these plates differently, so keep track of which one is which! Read on for another quiz question.

So you know which plate is which.

Not quite! You'll eventually need to differentiate between the two plates, but the tape won't help with this step. You will actually take the tape off before you need to assess the difference between the two plates. Try again...

All of the above.

Not exactly! The tape is an important part of the coating process, but it won't do everything! Make sure you follow every direction exactly to get the best solar cell possible. Try another answer...

Part 2

Assembling the Solar Cell

1

Place the carbon-coated plate onto the titanium-dioxide plate so the coatings touch. The plates should be slightly offset, about 5 millimeters (1/5 inch). Use binder clips on the long edges to hold them in place.

2

Apply 2 drops of an iodide solution to the exposed coating. Let the solution soak through the plate coatings so they're covered completely. You may want to open the binder clips and gently lift 1 of the plates up to allow the solution to spread over the entire surface.

The iodide solution will enable electrons to flow from the titanium-dioxide-coated plate to the carbon-coated plate when the cell is exposed to a light source. Such a solution is called an electrolyte.

3

Wipe excess solution off the exposed portions of the plates.

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Part 2 Quiz

How much of the plates should the iodide solution cover?

The entire plate.

Absolutely! If you need, you can open one binder clip and move one of the plates so the iodide solution completely covers the interiors of both plates. You should only need a couple of drops! Read on for another quiz question.

Half of the plate.

Not exactly! Even if this was all you needed, it would be difficult to only cover half of a plate! When you use binder clips to hold both of the plates in place, the iodide solution should spread over both plates. Guess again!

Iodide solution should leak out from between the plates.

Try again! If there is excess solution, wipe it up with rag. However, you shouldn't need too much iodide solution for your purposes! Try again...

Only put one little drop of iodide solution in the middle of the plates.

Nope! This won't be enough to make your solar cell effective. The iodide solution lets electrons move from one plate to the other, so it must be more spread out to be effective. Guess again!

Part 3

Activating and Testing the Solar Cell

1

Attach an alligator clip to the exposed coated sections on either side of the solar cell.

2

Connect the black wire of the multimeter to the clip connected to the exposed titanium dioxide coating. This plate is the solar cell's negative electrode, or cathode.

3

Connect the red wire of the multimeter to the clip connected to the exposed carbon coating. This plate is the solar cell's positive electrode, or anode. (In a previous step, you marked it with a plus sign on its non-conductive side.)

4

Place the solar cell next to a light source, with the negative electrode facing the source. In a school classroom, this can be done by laying the cell on top of the lens of an overhead projector. In a home setting, another light source, such as a spotlight or the sun itself, can be substituted.

5

Measure the current and voltage generated by the solar cell with the multimeter. Do this both before and after the cell is exposed to light.

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Part 3 Quiz

When should you measure the current and voltage produced by the solar cell?

While it is in direct sunlight.

Nope! Wait until later to test your solar cell. Make sure you have all of the wires and machines set up correctly or you'll get an incorrect reading! Guess again!

When it is in the dark.

Try again! Unless it gets dark immediately (like when you turn off the light in the room where you keep the cell), don't wait for it to get dark to test your solar cell! Make sure you follow all of the instructions exactly to get the most out of your solar cell! Pick another answer!

Before you expose the cell to the light.

Yep! Hook your solar cell up to multimeter both before and after you expose it to light. The sunlight is a great light source for your solar cell, but you can also use a spotlight or projector light. Read on for another quiz question.

The glass works because a side is coated by tin oxide, the rest of the glass doesn't really conduct or it would ground out. To get aluminum to work you would cover the sides and bottom with a non-conductive surface. Shrink wrap the bottom and sides or cover them in a layer of rubber or plastic.

Regular solar cells are made of semiconductors - so mostly silicone, Gallium arsenide, and on one or either side there are usually metal strips (busbar) to transport the electricity. That is a tiny amount of metal, which was often silver in the past, but is usually copper or aluminium nowadays. The cells will be put into a panel, which is made of an aluminum frame.

Tips

You can also make a solar cell by using 2 small sheets of brushed copper and setting 1 of them on the hot plate for half an hour until the copper turns black. Let it cool and remove the black cupric oxide coating, but leave the red cuprous oxide coating beneath it to serve as your semiconductor. You won't need to coat the copper sheet with anything, and you'll use a salt water solution as your electrolyte.

Warnings

Neither the coated glass plate nor the copper sheet semiconductor solar cells produce a large amount of power by themselves. Silicon is used in semiconductors because it is more efficient than either of the materials used in this article; however, individual silicon solar cells are assembled into solar panels.

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wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 26 people, some anonymous, worked to edit and improve it over time.